Gadolinium oxide thin films by atomic layer deposition

Atomic Layer Deposition of Gadolinium Oxide Films

“…[10] Gd 2 O 3 films can be grown by several techniques such as the sol-gel method, [2] electron beam evaporation (EBE), [4,6,9,13,14,17] sputtering, [12] ion-beam epitaxy, [5] molecular beam epitaxy (MBE), [10,19,21] oxidation of Gd metal films, [16,20,22] metal-organic (MO)CVD, [15,23] and ALD. [24][25][26] The growth techniques available may be distinguished on the basis of optimum deposition temperatures and suitability for large area substrate processing.…”

“…Cubic 95 nm thick Gd 2 O 3 films have been grown by using Gd(thd) 3 and ozone precursors at 300°C only. [24] Another study compares the ALD of Gd 2 O 3 from Gd(thd) 3 -O 3 and (CpCH 3 ) 3 Gd (Cp = cyclopentadienyl, -C 5 H 5 )-H 2 O [25] in the temperature range 150-400°C. While the Gd(thd) 3 -O 3 process exhibited a stable but moderate growth rate of 0.03 nm per cycle, the (CpCH 3 ) 3 Gd-H 2 O process showed growth rates increasing monotonically from 0.075 to 0.25 nm per cycle in the temperature range examined, which is usually indicative of thermal decomposition of the precursor.…”

“…In addition, relatively pure films grown at higher temperatures were only moderately crystallized, whereas strongly crystallized and textured films grown at 150°C were heavily contaminated with hydrogen. [25] It is necessary to search for a new precursor potentially able to provide water-assisted ALD with an appreciably 546 high and stable growth rate, structure, and purity. The most well-known precursor compounds for rare-earth metals in CVD are b-diketonates.…”

“…However, in conventional water-assisted ALD, b-diketonates have often demonstrated a too low reactivity with water which is most likely due to strong bonding (chelate effect) between the metal and the ligand, and also good sterical shielding of the largely ionic metalto-ligand oxygen bonds. Even if the films are deposited with ozone as an oxygen precursor and b-diketonates, the resulting films may contain considerable amounts of carbon, as shown in the case of Gd 2 O 3 [25] or La 2 O 3 [27] growth. Recently, rare-earth oxides have also been deposited by ALD using donor-functionalized alkoxides, amidinates, silylamides, and cyclopentadienyl compounds.…”

L X-Rays RYIED Oscillations and Proton-NMRD of Gd2O3 Nanoparticles

“…All the parameters in the right-hand side of the equation are to be taken as effective parameters. In (5), the following was considered: (1) r GdH is the distance between the water proton and the centre of the crystal core, (2) S was assumed to be 198 μ B by considering a spin density of 3.86 μ B /nm 3 , calculated from a lattice constant of 1.0812 nm determined by Niinistö for a cubic body-centred crystalline structure Gd 2 O 3 nanoparticles [33], (3) the τ ck are effective times characteristic of relaxation times defined as…”